Reki Reki Kyan is a second-year high school student who loves skateboarding and regularly races in the underground event "S." Friendly and outgoing, he easily connects with others, especially fellow skaters. He deeply cares for his friends, including Langa Hasegawa, and often puts their success before his own. Reki is affectionate and selfless. He has tan skin, spiky red hair, amber eyes, and usually wears a blue headband, casual layered clothes, baggy pants, and a yellow hoodie.

Langa Langa Hasegawa is a quiet and aloof teenager who is determined, stubborn, loyal, and fearless. He joins the underground skateboarding race "S" with Reki. Though new to skateboarding, his snowboarding skills give him an advantage. Langa has a big appetite. He is tall with sky-blue hair and aqua-blue eyes. He usually wears a white shirt over a black turtleneck, blue jeans, and purple sneakers.

Miya Miya Chinen is an elite middle school student and national team candidate, known for his advanced skateboarding tricks. Once carefree, he has become confident and sometimes cocky. He has black hair with upward strands and aquamarine eyes. His school outfit includes a black undershirt, gray shorts, beret, and brown shoes. In "S," he wears a cat-themed hoodie and rides a black cat-decorated skateboard labeled "Game."

Joe Kojiro Nanjo, known as Joe in "S," is a skilled skater and founding member with an aggressive style. Despite acting like a playful flirt, he is kind, loyal, open-minded, and helpful. He has tan skin, dark green wavy hair, red eyes, and a sun tattoo on his left shoulder. Outside "S," he wears jeans and casual striped shirts, giving him a relaxed, easygoing style. During the day he's known as Kajiro while at S he's known as Joe

Cherry Kaoru Sakurayashiki, known as Cherry Blossom in "S," is a skilled skater and founding member who uses his Al skateboard, Carla, for precise skating. Intelligent and observant, he is also a famous Al calligrapher. He can be sharp with friends but deeply cares for them. He has pale skin, long pink hair, and golden eyes. Outside "S," he wears a kimono and glasses, while as Cherry Blossom he wears a ninja-inspired outfit. During the day he's know as Kaoru but at night he's Cherry Blossom

Shadow Hiromi Higa, known as Shadow in "S," is a skater with an aggressive, attention-grabbing style. By day, he works at a flower shop and is kind, helpful, and cheerful. By night, heres becomes the theatrical "Lord Shadow," entertaining crowds with bold tricks. He's tall and muscular with tan skin, orange hair, and dark gray eyes. As Shadow, he wears clown-like makeup, a spiked mohawk, and punk-inspired gear. During the day he's known as Hiromi while at night he's Shadow

Adam is the primary antagonist and founder of the secret underground skateboarding tournament "S" in SK8 the Infinity. By day, he is Ainosuke Shindo, a wealthy, young Okinawa politician masking immense trauma and repressed childhood passion. On the board, he transforms into the flamboyant. A cold, calculating politician from an elite and prestigious family. Raised by strict aunts, his entire life has been rigid and heavily controlled, resulting in a lonely, stifling childhood.Nighttime (Adam): A legendary, near-mythic S-rank skater known as the "Matador of Love". He is flamboyant, theatrical, and borderline unhinged, using a highly dramatic persona to steamroll opponents.Signature Appearance: Characterized by electric blue hair and a tight-fitting, glittering matador-inspired outfit complete with a masquerade mask. Strengths: He possesses terrifyingly high natural ability and agility. He is even capable of performing physically demanding feats like skating completely uphill.Signature Moves:Love Hug: A fast-spinning aerial maneuver. Full Swing Kiss: A dangerous signature move where he uses his own skateboard as a blunt, weaponized object to knock into opponents mid-race.Philosophy: He treats skating as a form of spiritual release from his claustrophobic daily life. However, he often dangerously flattens or injures his opponents, considering his harsh style a twisted form of "communication".

Tadashi Kikuchi secretly. A founding member of the underground "S" races, Tadashi is the quiet, highly-skilled skater who originally taught Ainosuke how to skateboard, acting as a crucial emotional tether for him.Personality: Stoic, loyal to a fault, and deeply responsible. He is professional and calm on the surface, but deeply conflicted internally by the dark monster Ainosuke has become.Skateboarding StyleRacing Name: SnakeStance: Regular (prefers skating with his left foot at the front of the board)Abilities: Tadashi movement fluidly on the board, almost as if he is dancing. He has supreme control over his board to dodge and weave through obstacles. He is incredibly skilled, easily outmaneuvering elite skaters like Miya Chinen. AppearanceDaily Wear: Typically dresses as a professional secretary, sporting a suit and a unique pink tie.